Vacuum-pump apparatus.



R. BBRRENBERG. VACUUM PUMP APPARATUS. APPLICATIONv FILED MAY 29, 1909.

Patented sept. 10,1912.

2 SHEETS-SHEET l.

WAT-[J5EE EFE. A@ l R. BERRENBERG. VACUUM PUMP APPARATUS.

APPLIOATION FILED 11111129, 1909.

1,053,8,07'5 Patented sept. 10,1912.

2 SHEETS-SHEET 2.

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" ES' PATENT OFFIGE.

` BEINOLD BERRENBERG, OIF-BOSTON, MASSACHUSETTS.

VACUUM-PUMP APPARATUS.

Application led May 29, 1909. Serial No. 499,239.

To all whom it may concern:

Be it known that I, REINOLD BERRENBERG, a citizen of the United States, and resident of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful improvement in Vacuum-Pump Apparatus, of which the following, taken in connection with the. accompanying drawings, is a specification.

My invention relates to that class of rotary vacuum pump apparatus in which an extremely high degree of rareication is required.

Illhe object of the invention is to provide a very compact apparatus which will produce and maintain a practically perfect vacuum.

Accordingly, a feature of the invention contemplates the provision of a plurality of rotaryvacuum pumps acting 1n series., comprising a primary portion and a secondary portion, and Wholly immersed in a tank of oil. The primary portion of the series, which is lconnected to the article to be exhausted, exhausts into the space above the oil in the tank, preferably into one of the domes, and the secondary portion of the series draws from the space above the oil, preferably from a second dome, and exhausts into a catch tank or muiiler, which is. open. to the atmosphere.

A further feature of the invention consists in immersing not only the pumps but the motor and the cooling device in deaerated oil.

With the above object in view, the invention consists in the vacuum pum apparatus hereinafter described and particularly defined in the claims, the advantages of which will be obvious to those skilled in the artfrom the followingI description.

ln the accompanying drawings, Figure 1 is a plan showing the interior of one of the pump tanks and the location and arrangement of the pumps and the motor, also a part of the pipe system for cooling the oil in the tank. In this view the cover of the oil tank is' removed so that the interior may be seen. Fig. 2 is a transverse, vertical section taken on line 2-2 of Fig. 1. .Fig 3 is a longitudinal,"vertical section of the apparatus. Fig. 4 is a transverse,- vertical section taken online 4-4 of Fig. 1. Fig. 5 is a transverse, vertical section taken on line 5-5 of Fig. 1.

As illustrated in the accompanying drawspecicauon of Letters Patna.

indicates the amount o Patented Sept. 10, 1912.

ings, the apparatus comprises a metallic tank A, having a cover B. This tank must be made as much as possible without. joints or openings, and whenever a joint or opening is made gaskets and packings are to be used, so that the tank will be as nearly oiland air-tight as it is possible to make/it. 'When in use it is filled with the best vacuum oil to such a depth as to entirely immerse the pumps and the motor therein, the spaces in the domes F and L1 being free of oil.

Within the tank two rotary vacuum pumps P and P1 are placed. These two pumps, a section of one of which is shown in Fig. 2, are alike in internal construction and may be briefly described as follows: Within the casing P a rotary piston-carrier G rotates` on its axis G". The rotary piston-carrier Gr has a series of radial pistons G1 G1, which are arranged to slide freely in a radial di-l rection, their motion being governed by the eccentrically placed ring G2 which is held in place by a friction roll at G4. These need not be more fully described as they are of well known construction.

The pump P, which may be termed the primary pump, draws air from the article to be exhausted through the pipe D, which is surrounded by an oil-j acketing pipe C. This pump exhausts through the pipe into the dome F above the oil in the tank. The pump P1 shown in elevation in Fig. 4, which may be termed the secondary pump, draws from the dome L1 through" the pipe L4 and exhausts through the pipe N into the oilcatch tank N1. The catch-tank N1 is open at the top and has a si ht gage N2 which oil in the catchtank and when it has accumulated a certain amount the cock N is opened and the surplus oil allowed to run back into the main tank.

By the above described arrangement and construction it may be understood that the primary pump P pumps direct from the lamp bulb or other article to be exhausted and discharges into the dome F. A s the secondary pump P1 is also in operation 1t will be understood that there is already'a partial vacuum in the dome F and also 1n the dome L1. U forms a partial vacuum above the o1l and wi draw incidentally from the vacuum oil any air or gases that `may be in it, and will assist the primary pump P in making a better Now, the secondary pum vacuum. That is, the two pumps acting in seriesI will make a better vacuum than one I pump alone would make. v

The two pumps P and P1v are driven by thesame shaft S that is also the shaft of the motor M. The motor M has an interv nal construction substantially like the pump P but the inlet and outlet are diierent in size, that is, the inlet vport H I-I1 is made smaller than the outlet port K1 K. That is done so that there may be a free passage for the exhaust Vand thus prevent any back pressure on the revolving pistons. The motor is drivenl by a vacuum oil under pressure.

The -pip'es Hand K at the places where they v pass through the case of the tank are 'made tight by metallic packing or by cemented or solderedjoints; as these are'rlgidly xed lthe joints may be easily made' absolutely airtight.

. in the tank and are 'provided with acon-A For preventin the oil in the tank from becoming too hig ly heated by the action of the machine, sets of pipes T T are placed stantcurrent of cold water.'

The oil that is used fordriving the motor M has more or less air in it. To prevent this containedair from passing through the bearing of the shaft S, the following device is l` used: A stuiiing box R of usual construction is provided and is inclosed in a casing R8, `having a chamber R2, which is lled with vacuum oil, and a second stutiing box R1 is provide(J on the outside of the casing R3. This construction insures an air-tight joint about the shaft S, -and prevents ai from getting into the oil in the tank. -v

I claim y 1. A vacuum pump apparatus, comprising a primary rotary air pump and a secondary rotary air pump both inclosed in a tankand wholly immersed in 0il,`said primary pum discharging into the tank. and said secon i 'l ary pump drawing from the tank so as to free the oil from anyincluded ai`1` or gases,

and acting in series with said primary pump to produce a high degree of vacuum, substantially as described;

'2. A vacuum pump apparatus, comprising y a tank containing o1l. andhaving a pair of domes above the level of the oil, a primary rotary air pump and a secondary rotary air rotary air pump having its discharge communicating with one of said domes, a secondary pump having its inlet communicating with the other of said domes, a fluid driven motor for driving said pumps, all of said pumps and motor being inclosed in the tank and wholly immersed in the'oil, said secondary pump operating to free the oil from any included air or gases and acting -in series with said primary pump to produce a high degree of vacuum, substantially as described.

4. A vacuum pump apparatus, compris-4 ing a closed tank containing oil with a free space above the oil, a primary rotary pum unit having an inlet adapted to be connecte to the receptacle which is to be exhausted and an outlet communicating with the free 4 l .space above the oil, and a secondary pum unit having an inlet communicatin wit said free space and an outlet communlcating with the atmosphere, said primary and secondary units operating in series to produce l a high degree of vacuum, substantially as described.

In testimony whereof, I have signed my name to this specification in the resence of two subscribing witnesses, on t is eighth day of May, A. D. 1909.

REINOLD BERRENBERG. vWitnesses:

FRANK G. PARKER, WILLIAM EDsoN. 

